1. Field of the Invention
The present invention relates to an improved bristled article and more particularly to an improved toothbrush. The bristled article has a tuft cavity wherein the cross-sectional area of the tuft cavity decreases such that the tuft cavity is broadest at a surface contiguous to an open top end of the cavity and narrows toward a bottom closed end of the tuft cavity. With all other components left unchanged, this decrease of the breadth of the tuft cavity results in a greater packing factor and therefore better bristle retention in the smaller closed bottom end portion of the cavity. The bristled articles embodied in this invention include toothbrushes, hairbrushes, clothes brushes, industrial brushes, brooms, copier brushes, mascara applicators and the like.
2. Description of the Related Art
Bristled articles of the related art may be produced by injecting a thermoplastic material into a mold to form an article base, and subsequently mechanically anchoring the article base with tufts of bristles.
A potential problem with bristled articles of the related art described above is that the bristles may loosen or fall out of their tuft cavities. The effectiveness of the bristled article is thereby decreased. Loss of bristles from a tuft cavity reduces the number of exposed bristle ends and available effective surface. Further, loss of bristles in a tuft cavity reduces how tightly and securely the remaining bristles are retained in the cavity. In addition to lowering efficacy of these articles, loss of bristles reduces the convenience with which such bristled articles can be used. Understandably, users prefer not to use articles which leave stray bristles behind after use.
Some types of toothbrush bristles historically have greater tendency for bristle fall out and therefore need increased bristle packing to improve bristle retention. Different diameters of bristles are used by those skilled in the art to achieve a range of textures in toothbrushes. Toothbrushes have bristles ranging from 0.003 inch to 0.012 inch in diameter, more commonly from 0.005 inch to 0.012 inch. Individual bristle fallout is more likely to occur in toothbrushes with small diameter bristles or an insufficient number of bristles in a tuft.
Attempts to reduce the incidence of loose bristles in the brushes of the related art have not been wholly successful. One such approach involves the insertion of increased numbers of bristles into each tuft cavity of the bristled article. A serious attendant problem with this approach is that splaying of the bristles occurs when too many bristles are crowded into a tuft cavity creating an undesirable "bushy" appearance conveying a perception of a defective or worn brush.
It is an object of the invention to provide such a bristled article having a tuft cavity configuration that increases retention of the anchored bristles without attendant splay.
With the above and other objects in view, the present invention comprises the combination and arrangement of parts hereinafter more fully described, illustrated in the accompanying drawings and more particularly pointed out in the appended claims, it being understood that changes may be made in the form, size, proportions, and details of construction without departing from the spirit or advantages of the invention.